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Category: functors Component type: type


Equal_to<T> is a function object. Specifically, it is an Adaptable Binary Predicate, which means it is a function object that tests the truth or falsehood of some condition. If f is an object of class equal_to<T> and x and y are objects of class T, then f(x,y) returns true if x == y and false otherwise.


Rearrange a vector such that all of the elements that are equal to zero precede all nonzero elements.
vector<int> V;
partition(V.begin(), V.end(), bind2nd(equal_to<int>(), 0));


Defined in the standard header functional, and in the nonstandard backward-compatibility header function.h.

Template parameters

Parameter Description Default
T The type of equal_to's arguments.  

Model of

Adaptable Binary Predicate, DefaultConstructible

Type requirements

T is EqualityComparable.

Public base classes

binary_function<T, T, bool>.


Member Where defined Description
first_argument_type Adaptable Binary Predicate The type of the first argument: T
second_argument_type Adaptable Binary Predicate The type of the second argument: T
result_type Adaptable Binary Predicate The type of the result: bool
equal_to() DefaultConstructible The default constructor.
bool operator()(const T& x, const T& y) Binary Function Function call operator. The return value is x == y.

New members

All of equal_to's members are defined in the Adaptable Binary Predicate and DefaultConstructible requirements. Equal_to does not introduce any new members.


See also

The function object overview, Adaptable Binary Predicate, not_equal_to, greater, less, greater_equal, less_equal

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